Process for the production of hydrogen from gas mixtures containing hydrogen.



0. VON LIN DE. PROCESS PoR THB PRODUCTION 0F HYDROGBN FROM GAS MIXTURES GONTAINING HYDROGEN. APPLIOATION FILED 0OT.10.1910.

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UNITED STATES PTEN T OFFICE.

CARL YON LINDE, OF MUNICH, GERMANY.

PBOSS FOR THE PRODU'ICTION 0F HYDROGEN FROM GAS MIXTURESCONTAINING HYDROGEN.

Specification of Letters Patent.

Appliation mea october 1o, 1910. serial No.

To all whom 'it may concern:

Be it known that I, CARL voN LINDE, of Munich, 'in the Kingdom of Bavaria, Germany, have invented certain new and useful Improvements in Processes for the Production of Hydrogen from Gas Mixtures Containing Hydrogen; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to an improved process for the production of hydrogen from gas mixtures containing hydrogen.

There areseveral processes known for the separation of gas mixtures through liquefaction and fractional distillation, but they are not adapted to the separation of gas mix- -tures which contain hydrogen, because the liquefaction of hydrogen can only take place at a temperature so low that all other gases at this temperature exist only in the solid state.

The object of the above invention is the extraction of. hydrogen, by separating it from gas mixtures containing hydrogen (such as illuminating gas or water gas) in such/a manner that the less volatile constituents of the as mixture are condensed through the in uence of a reduction of temperature which may also be combined with an increase in pressure. The reduction of the temperature to such a degree as to bring about liquefaction of such constituents, as for example carbon monoxid and nitrogen, of which the critical temperatures are very low, is brought about in such a way that the gas mixture is relined, in that it is comf pressed, the heat of compression being trans- 40 erred to cooling water, and then' in connection with a heat interchanger, it is expanded r with the performance of internal or-external work in a manner similar to that in the wellknown processes for the liquefaction of air of von Linde and Claude. From these latter,

- the present process is however `tdifterent,

since the separation of the gas mixture into a liquid portion containing the less volatile constituents and a' gaseous ortion co taining principally hydrogen, ta es place b fore expansion of the compressed gas m' ture and for that reason the expansion mu t take place in Atwo separate apparatus,whi e with the` process for the 'liquefaction and fracand then the separation of the gas mixture' into its component parts follows afterward.

1f the expansion is accomplished as in the von Linde process without the performance of external work, the gas mixture will not furnish the requisite cooling effect if it contains a large proportion of hydrogen, because the inversion-temperature '1ies very low and to reach this, cooling by expansion without external work cannot be ap lied. In this case the necessary cooling elect is supplemented by the use of liquid air or liquid nitrogen to remove some of the heat of the gas mixture. If the compressed gas mixture is brought to a sufficiently low temperature before expansion, either With or without the aid of liquid air or liquid nitrogen as the case may be, then a separation of all the constituents of the mixture ywith the exception of the hydrogen takes place as the result of condensation to an extent determined by their partial pressures corresponding to the temperature attained by the pressure applied. As these constituents of which the boiling points are lower than that of nitrogen, together with hydrogen itself do not need to be considered, liquefaction is thus obtained of all the other constituents with the exception of a very small residue by employing liquid nitrogen as a cooling agent. If, however, it is desired to separate this residue as far as possible the cold hydrogen, from which most of the constituents of the gas mixture have already been separated, and which is still under high pressure and at the tempbrature of ebullition of liquid air or liquid nitrogen, can be utilized in conjunction With a special interchanger in the same Way as in the case of apparatus for the lique- Patented Mar. 12, 1912.

faction of hydrogen, and in this-way a lower temperature can be attained than that of the evaporating nitrogen. If this low temperature thus obtained in the heat interchanger is transferred to the compressed hydrogen before expansion the remaining constituents of the gas mixture can 'be separated even to the last traces. y

In the ccompanying drawings, Figure 1 is a diag ammatic representation of one form of pparatus for carrying out my process. Rigs. 2 and 3 are similar views of "l in temperature each with added feathe same apparatus,

to use under bring about stoppages in the liquetying apparatus,le.'g. carbonio acid and sulfur compounds. In its passage through the apparatus tothe vessel B, the gas mixture is reduced in temperature to such a degree in the temperature-interchanger C, that the greater part ofthe constituents of the gas mixture are liqueied and collect inthe vessel B.' The liquefied portion iiows out of this vessel through the expansion mechanism D into the interchanger C, evaporates and thereby removes heat from the compressed gas mixture iiowing through the apparatus. The products of this evaporation, e. g. carbon monoxid escape at E, after an interchange-of temperature with that of the compressed gas mixture passing through the apparatus and can be applied in any manner desired. The portion of the gas mixture which isy not liquid (hydrogen and the-remaining constituents) after passing through the expansion mechanism F ows through the temperature-interchanger C in 'an opposite direction to that of the compressed gas mixture and escapes out of the apparatus at G at normal temperature.

In Fig. 2 is diagrammatically represented an arrangement of apparatus generally similar to that shown in Fig. 1 but to which' a vessel or pipe M is added in which atmospheric air or nitrogen is allowed to enter at H in the liquid state and escape at I in the -form of gas, it the composition of the gas mixture is such that it does not produce a suiicient cooling eect yon expansion and thus renders the use of liquid air or liquid nitrogen necessary.

In Fig. 3 I have shown howa heat interchanger K and the separating vessel L, may be added, if it is desired by separate expansion and the use of a further reduction attained by means of this expansion, to liquefy all other constituents and thereby to liberate, them as far as possible rom the hydrogen. After the largest portion of the constltuents of the gas mix-l ture has become liquefied in the heat-interchanger C, and has collected in the vessel B, the remaining portion which is still in the form of gas and consists principally of hydrogen flows through theinterchanger K and is thereby p ture by the counter-current of expanded hydrogen. As the result of this practically all the remaining constituents of the gas mixture except hydrogen are here liquefied A lhydrogen from a mixture of gases,

further reduced in temperaand collect in the vessel L, and are allowed to unite with the liquid separated in the vessel B, and then to expand as in Figs. 1 and 2 through the throttle valve D to evaporate in the interchanger C, to become raised in temperature and to ultimately escape at E. The portion which does not collect in L but remains in the gaseous form and which isl now nearly pure hydrogen, is expanded throughv the throttle valve F, passes in counter-current to the previously partly purified hydrogen through the interchanger K and then in counter-current to the compressed gas mixture in the interchanger C and ultimately passes out at G.

Having fully described my invention what. I claim as new and desire to secure by Letters-Patent, is, l

l. In the production of practically pure hydrogen from a mixture of gases, the separation of, a portion of the mixture by liquel faction in such a way that the incoming compressed gas mixture is brought into heat interchanging relation with separated portions of the gas mixture previously expanded, and is split up into a liquid portion composed .principally of all other'constituents and a gaseous portion composed principally of hydrogen and that then both these portions are individually expanded and are vled in two separate streams in counter-current and heat interchanging relation to the incoming compressed fgas, mixture.

2. In the production of practically pure the separation of a portion of the mixture by liquefaction in such a Way that the incoming compressed gas mixture is brought into heat interchanging relation with separated Vportions of the gas mixture which have been previously expanded and subsequently cooled by liquid air or liquid nitrogen,

whereby the compressed gas mixture is split u into a liquid portion composed' principally of all the other constituents and a gas. eous portion composed principally of hydrogen, and that then both these portions are individually expanded and are led in two separate ,streams in counter-current and heat interchanging relation to the incoming g 3. In the production of practically purel hydrogen from a mixture of gases, the separation of a portion of the mixture by liquefaction in such a Way that the incoming compressed gas mixture is brought into heat` interchanging relation with separated portions of the gas mixture previously expanded and subsequently cooled by liquidair or liquid nitrogen under a reduced pressure, whereby the gas mixture is lsplit up into a liquid portion composed principally of all the other constituents, and a gaseous portion composed principally of hydrogen, and that then both of these portions areinarate streams in heat interchanging relation l compressed gas mixture is brought into heat interchan'ging relation with separated pordividually expanded and are led in two septo the incoming gas mixture.

4. In the production of practicall pure hydrogen from a mixture of gases,l t e separation of a portion of the mixture by liquefactio'n in such a way that the incoming portion prior to its expanslon into heat interchanging relation with a separated portion of such gaseous portion previously expanded, and flowing counter-current thereto, whereby practically all the remaining 20 constituents except the hydrogen are liqueed before expansion by the reduction of their temperature thus produced and are led away separately.

In testimony whereof, I have signed this 25 specification in the presence of two subscrlbmg witnesses.

CARL voN LIN DE.

Witnesses:

A. V. W. Co'r'rn, MATHILDE K. HELD. 

